Some internal combustion engines utilize a compression device such as a turbocharger to increase engine torque/power output density. In one example, a turbocharger may include a compressor and a turbine connected by a drive shaft, with the turbine being coupled to an exhaust manifold side of an engine and the compressor being coupled to an intake manifold side of the engine. In this way, the exhaust-driven turbine supplies energy to the compressor to increase the pressure (e.g. boost, or boost pressure) in the intake manifold and to increase the flow of air into the engine. Some engines, such as V-engines, utilize twin turbochargers each positioned on respective intake/exhaust sides and configured to increase the boost pressure delivered to respective cylinder banks. In some configurations, each turbocharger may include a wastegate to control the amount of gas reaching an associated turbine and thus the boost pressure delivered to the associated cylinder bank. Each wastegate may in turn be operatively coupled to an actuator configured to position a wastegate valve between a fully open and a fully closed position to achieve a desired boost. The actuators may be pneumatic, hydraulic, or electric, for example. Thus, in such twin turbocharger configurations two wastegates are each controlled by an associated actuator.
The inventors herein have recognized several issues with such approaches. In particular, v-engine asymmetries between cylinder banks, resulting from differences in exhaust system routing, exhaust manifold design, turbine housing casting design, and/or wastegate passage design, may create imbalances in positioning between the wastegates and thus the boost pressure delivered to each cylinder bank. Manufacturing variability and hysteresis within the actuators may further exacerbate asymmetry between the cylinder banks. As such, additional complexity may be introduced to wastegate control routines in order to compensate such asymmetry. Moreover, dual wastegate actuators increase cost and part count relative to configurations in which a single wastegate having an associated actuator is used.
Systems and methods for controlling dual wastegates via a single wastegate actuator are thus provided.
In one example, a system comprises a first wastegate comprising a first wastegate valve, a second wastegate comprising a second wastegate valve, and a wastegate actuator coupled to each of the first and second wastegate valves to vary openings of the first wastegate valve and the second wastegate valve according to desired boost.
In a more specific example, the first wastegate valve and the second wastegate valve are coupled to the wastegate actuator through a variable-length arm via respective linkages, the wastegate actuator being configured to vary a length of the variable-length arm.
In another aspect of the example, the first wastegate valve and the second wastegate valve are coupled to the wastegate actuator through respective plates via respective linkages, the respective plates disposed being inside a reservoir, the reservoir being configured such that increased fluidic pressure supplied to the reservoir pushes the respective plates outwardly, decreasing respective lifts of the first wastegate valve and the second wastegate valve, the reservoir being configured such that decreased fluidic pressure supplied to the reservoir brings the plates closer together, increasing the respective lifts of the first wastegate valve and the second wastegate valve.
In still another aspect of the example, the reservoir is configured to receive a hydraulic fluid from a hydraulic regulator via tubing, the hydraulic regulator fluidically coupled to a hydraulic fluid source.
In yet another aspect of the example, the reservoir is configured to receive pressurized gasses from a vacuum regulator via tubing, the vacuum regulator fluidically coupled to a vacuum source.
In the examples described above, control of dual wastegates may be facilitated via a single wastegate actuator at reduced part count, cost, and control routine complexity. Thus, the technical result is achieved by these actions.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.